The present invention relates to frame elements and systems and, more particularly, to foldable frame elements and systems.
Various folding frame systems for forming collapsible shelters and the like are known, such as those disclosed in my U.S. Pat. No. 5,230,196, U.S. Pat. No. 5,444,946, and U.S. Pat. No. 6,141,934, all of which are incorporated by reference. Those shelters, while generally well-suited for quick erection and for use in adverse environmental conditions, involve numerous parts and are designed for use for extended periods of time and in circumstances that can generally be anticipated. They are particularly useful in military applications where considerations of cost are secondary to the ability of the equipment to be successfully used under difficult environmental conditions.
In certain emergency situations, shelters such as those typically used by the military, while desirable, are often not practical. In disasters such as floods and earthquakes, the quantity of shelter needed for victims substantially exceeds the quantity of shelter available through collapsible shelters of the type purchased by the military. Moreover, the cost of such shelters, even if available, would be prohibitively expensive for most aid agencies and well beyond the means of the victims themselves.
Often, disaster victims are provided with crude shelters that are constructed out of any available materials, or provided with tents that are not intended for extended use. Usually, the shelters are poorly insulated and, in cold weather, they do not provide adequate protection from the elements. While these shelters are built or erected in the expectation that they will only be temporarily occupied, the reality is that the disaster victims often spend extended periods in these shelters. Survival is difficult where the shelters are not well-suited for adverse weather conditions.
It is desirable to provide a foldable frame system that is inexpensive to make, simple to erect, and that can be used as a disaster relief shelter, among various possible uses.
According to an aspect of the present invention, a frame element comprises a first scissor comprising a first and a second strut pivotably connected to each other at a first pivot point, a second scissor comprising a third and a fourth strut pivotably connected to each other at a second pivot point, and a hub to which the first and the third strut are pivotably connected, the first and second scissors being pivotable about the hub between a closed position in which the first, second, third, and fourth struts are substantially parallel to one another and an open, locked position in which the first and third struts define a non-zero angle with each other and abutment portions of the second and fourth struts contact receiving portions of the third and first struts, respectively, and prevent the first and third struts from pivoting beyond the non-zero angle.
According to another aspect of the present invention, a folding frame system comprises at least two frame elements, each frame element comprising a first scissor comprising a first and a second strut pivotably connected to each other at a first pivot point, a second scissor comprising a third and a fourth strut pivotably connected to each other at a second pivot point, and at least three hubs, each of the first, second, third, and fourth struts having first and second ends, the first ends of at least one of the first, second, third, and fourth struts being pivotably connected to at least one of the three hubs, the first and second scissors being pivotable about the hubs between a closed position in which the first, second, third, and fourth struts are substantially parallel to one another and an open, locked position in which the first and third struts define a non-zero angle with each other and abutment portions of the second and fourth struts contact receiving portions of the third and first struts, respectively, and prevent the first and third struts from pivoting beyond the non-zero angle, and at least three third scissors, each third scissor comprising a fifth and a sixth strut, the fifth strut being pivotably connected to one of the hubs and the sixth strut being pivotably connected to the second and fourth struts.